Over the past decade the survival of children with congenital heart disease (CHD) has improved significantly, leading to an increasing number of survivors. Recognized sequelae of surgery for congenital heart surgery include residual hemodynamic abnormalities and arrhythmias. It is now being recognized that the neurodevelopmental sequelae of this type of surgery are substantial. Specifically, many school age children are challenged because of problems with inattention and hyperactivity;that is, they appear to have attention deficit hyperactivity disorder (ADHD). There is evidence that ADHD is more prevalent in the post surgery CHD patients than in the general population. In addition, the CHD-ADHD patients seem to be under treated. Thus, the primary aims of this study include 1) to determine the prevalence of ADHD in the population of children with CHD undergoing surgery using cardiopulmonary bypass in infancy or early childhood;2) to compare the prevalence rates of ADHD associated with age of exposure to cardiopulmonary bypass as well as the effect of multiple exposures to CPB and different adjunctive support techniques that may be utilized;3) to identify and compare the variety of patient related, operative and postoperative risk factors that could affect the likelihood of developing ADHD, including type of congenital heart defect, genetic substrate, surgical procedure required, operative factors, and perioperative events;and 4) to test the safety and efficacy of stimulant medications used to treat ADHD in a postoperative cardiac population. While studies suggest that many of these children have ADHD and could potentially benefit from the standard stimulant drug therapy effective in most of the population, concerns over cardiac safety has severely limited its use in children with heart disease. As no safety studies of the stimulant drugs in this population have been attempted, we propose a randomized double blind placebo controlled trial of the two most commonly used stimulant medications to determine their efficacy and true level of risk in postoperative cardiac children. This information will allow clinicians to use these potentially effective drugs safely in appropriate cardiac patients, improving the quality of life for these children with special needs. The Children's Hospital of Philadelphia (CHOP) Cardiology Division and Cardiac Center have a distinguished history of clinical innovation and excellence in cardiac care, a high volume program with expertise is all areas of pediatric cardiology and cardiothoracic surgery. The faculty of the CHOP and Cardiac Center are experienced investigators in multicenter clinical trials and studies. The institutional strengths and infrastructure support clinical investigations and enhance the likelihood that the aims and long term goals of the Pediatric Heart Network will be achieved. (End of Abstract).